Many different kinds of materials interact with light and other electromagnetic fields. These materials can be configured to control light in various ways, forming the basis for optical devices, such as lenses and prisms. The optical properties of a typical optical device are related to how the device is configured and on the material of which the device is composed. A typical lens, for example, can be composed glass or plastic and can be configured to bend an incident beam of light to either converge or diverge. Optical fibers and waveguides are examples of other types of optical devices formed by stretching various combinations of glasses or plastics to guide light over large distances.
The quality and diversity of typical optical devices is, at least in part, limited by the available range of electromagnetic properties of the materials comprising the optical devices. As a result, existing materials exhibit only a fraction of the electromagnetic properties that are theoretically available. One way to expand the available range of optical device properties is by adjusting the composition of the optical device materials at the molecular level. Another way is to broaden the definition of a material to include artificially structured materials in which the electromagnetic response results from a macroscopic patterning or arrangement of two or more distinct materials.
In recent years, there has been an increasing interest in artificially structured materials that expand the range of electromagnetic properties beyond the inherent properties of typical materials used to produce optical devices. Artificially structured materials with designed inclusions can exhibit exotic and unique electromagnetic interactions with particular portions of the electromagnetic spectrum not inherent in the individual constituent materials. These artificially structured materials, called negative index materials (“NIMs”), have the potential to fill critical voids in interacting with the electromagnetic spectrum where typical material response is limited and, therefore, enable the construction of novel devices. In particular, NIMs can be configured to exhibit a negative refractive index for particular portions of the electromagnetic spectrum, a property not found in devices composed of typical materials, have drawn significant interest, underscoring the potential of NIMs to facilitate new developments in controlling electromagnet radiation.